Heat exchanger



55512 1951 v DHE N 2,550,550

HEAT EXCHANGER Filed Jan. 21, 1946 v I 23 v 9 F/G. 5 F/5.. 6

I Wye/ Mar #11; Hero)? Patented Apr. 24, 1951 HEn'n-ExcnANG-En Huh:Dl.lzleron,.Q filiemont,Quebec Cantabile Application Januarv zl, 1946'S'erial Nm @425 This inventioni.relates;to.imgirovementsdnzths;

beunderstoodthe inventionis snottherebyilimitedi.

to that application but; extendsito otherr typesoofir heatiexchangerswTheiprimary object of; the invention isitogprna vide,imcombinationxwithia; construction-imam eral according to mysaidiear-l'ien; invention; ands; with the retention-of allitheadvantagesrthereofi; means for holding." the; exchangere tubes:against... creeping through: the. packing thereof and; through. th tube;plates and; against; oscillatory;

movementwhichv tends tofiloosen theipacking cause leakingp Ar. further.objecta.is.:. to; provide: construction permitting :free. movement. of;tubes. in expansion and; contractioni due toatempera-a tul e changes;without damage. to. packing; and: with: exclusion of grit;muwon'scaleifromithez.

' clearancebetween the'tubeszandttheitube holding.

means. A stilhfurther object:isitozprovideaprotece tion againstrdryingout tofu the packingi Wham. an

exchanger istemporarily: outofiservice... Another.

obiect is to provide a construction:which.zisieasei ier and less:expensivetoiproduceiand} whicinmay; more easily and quickly assembleds.thanthe: cone. struction-nowin generala use; Still: another obao ject isto; provideconstruction;apphcableztm exist-t. ing exchangers having the:usualz internallyr threaded packing chambers; either'to convertrthe.same to embody the-1 featuresc ofsthisi and; of former invention on asianaemergency:- substia, tute for the: usual connectionobetweern tubesiand tubeplates. Various othen objects: anduthe; aria, vantages of'theinvention may; be v ascentained; from the following descriptioniandztheiacconn;

panying draiwingsi v 'Ihe inventiom CQnsiStS-l esSentia-Hyu 1mproviding}. a heat exchanger having. packing. receiving-z lies cesses inthe tube p1ates-,.thereof: formed; to; n 1;. ta-im packing thereinindependentlit of: anyo addict. tionak retaining; means combina on:with.

means. adapted: to. hold the. enchaneera tlihQ ii against creepingthrough the: tube pla es and: packing; toiexchide; foreign matter: frombetween; mambeseandetheiholdi a-meansi h r for to; protect.thenaokingyaea ns the effect o woe. bra o .andt against dra utwhe. thechanger stem-po ar ye atof In gr at de aii,p.. he n-yen insist features;an c m. a ns. fizi fl ll' fi he closed eaether w t a l su h. modifl aicmr esitant-a d: ubstitutions; a v sher araw th'ni lae we iqathe eleven.efli leemen In. the accompanying. dIaWii1gSh formina. part:

or this specification; which illustrate. hfiikf lfmz.

of the invention nowzpreferredi'for new onstruqev. tion; andr further:iilustnatei modifications theme. ofzfor the adaption ofirtheiinventiomto.existin condensers; but-to.atheidetailsiofrail IOf': whichitheainvention is:.-not;confine.d3i r Fig; .1; fragmentaryiside:elevatiomofsaiconn denser.

Fig; Zwis: an:- elevation;- of iar-frag'mentcogf a tubse plate.ShOWi'Ilg. the: ends? of? tubes: and; netainingr means therefor:

Fig.*.-. 3 is; a; section: om the line: 3&3: of. Fig. showing: the.relatiom of; the: pants: asinnwz prev; ferredzfor new. construction.

Fig. .v 4. is! a; section; simil'an to.. that:. of 3;.

showingmodifications;

Figs; 5*,ami '6tarei sectionsisimilanto thatioiszfi a 3, showing waysofradaptingithe inventionetoiene; istingcondensers;

Reiernin imoreparticularly-to.theidrawingsr t1; designatest condensentube; 131817.381 and I22 01k; densertubes mountain in the..- nlatesi...tuba. platesiare formed: with wen wrestle; therein ionpassage. oife the.tubes,.. which. anentures: are. 115113.

1 ally.locaztect as close, together ass.is.; pQSSib1e; cone sistentwitmadequate strenethrcf thatube plate.

so as to provide the maximum number of tubese withini a. given;513343332. Eacln apenture: I132; comprises; three, ortions: namely;aniinner portion I43; .amintermediate; portior-inlfiaand.anaoutelt D9.time 61. Theinnenmortion I-Jhis c-linsirioal; andr oti'suchodiametergthat thatub iszani eas -s1id' in nttnerein-Theiintermediate;.portiqnrtiaiao larger-diameter; than theiinnereportion smasutila;

7 provide an annular packing space around the-3;

tuba; thetshoulderr H between the jinner: andr the intermediateportions-L being; preferablyfla-ti, and: normal to. the; aperture axis;but; may; be; other wise formed: The. circumierentialiwalla 0:: meme.tern-mediates. portion; is: tapered through at: leasia a; part of its:depth; towardztheouten end, of the;

aperture so as to.; form a-.-.shon1der, fafiin a the; hou de I; butmast-be cylindrical n; ts-Amen portion, as. showniati with R -.42. he; fren ial; wall; o he outer ner ure o Ht: s preferably y i dr al andeferablyw ehtlryi greaterdiameter-than t e outer 3 505 the lia fifim d pon L5 e, as e; rz nvisle. a, nar ow:- shoulder. l9,- at: the junction: 02 he intermediate nd: outerportions. Preferably-the; diametepot: heu epo Hi. is. anprot me r meme; as-the maximum diameter of the.intermediate portion; as. shownsin Fig, abut-may, bed v same. diameteras the out r nd: f. he int mediate p rtion... asshown in E a, which.case, there. no, shoulder. t9... The} depth oi. the; outer. portion ismaterially greater'than m lon. gitudinaliexpansion of the tube l2, prefeiablgl three-to. five. times he xp nsi n.

The. maximum diameters. of. the. nertutqa it In the outer portion l6 ofeach aperture there is provided a metal washer or ring 20 whichpreferably completely fills the aperture around the tube and which is aneasy sliding fit' on' the aperture wall and on the tube, so that thetube may move freely through the ring when expanding or contracting.Normally the ring rests on the seat I9 and the outer end surface of thering is flush with the outer surface of the tube plate I I. The bore ofthe ring is flared from the inner end surface of the ring, or from aline adjacent the inner end surface of the ring, as shown at 2|, towithin a short distance of the outer end surface and is parallel, orcylindrical, from the flare to the outer endsurface of the ring, asshown at 22. The depth of the parallel portion 22 is at least as greatas the longitudinal expansion of the tube when heated in service. Thetotal angle of flare is preferably from 10 to 30.

The packing now preferred is a single sleeve 23 of water swellablecompressed fibre which, in

its dry condition, is an easy sliding fit on the tube and intothe smallend of the intermediate aperture portion [5. The length of the packingsleeve is preferably only slightly less than the depth of theintermediate aperture portion.

The sleeve 23 is preferably composed ofthat type of material formed bywinding a ribbon of paper or the like impregnated with a suitablebinding agent, around a mandrel until a suitable wall thickness is builtup and then compressing the tube in its radial direction. Sleeves ofsuch material, when exposed to water, swell radially but 'do not swellappreciably in their axial direction.

If desired, instead of using a single sleeve, I may use a series ofrings or washers 2i of the same material, as shown in Fig. 4. Thissubdivision of the packing into rings facilitates penetration ofmoisture to all parts of the packing and"thereby expedites swelling ofthepacking but has the disadvantage of longer assembly time.

The length of the tubes l2, when cold, is preferably less than thedistance between remote faces ofthe tube plates H by about twice thelongitudinal expansion of the tubes when heated to maximum workingtemperature, so that, when cold, the ends of the tubes are slightlybelow the outer surfaces of the tube plates, as shown. Thus, even if oneend of a tube remains fixed, the longitudinal expansion resultant ofheating to maximum working temperature will not cause the free end ofthetube to project beyond the surface of the tube plate. In this wayturbulence of fluid in the condenser is avoided.

f After the tubes are in place in the tube plates and the packing andend rings have been inserted at both ends of the condenser in the mannershown, both ends of each tube are flared or radially expanded intosurface contact with the flared bore portions 2| of the end rings 20.The radial expansion of the tube ends is only that sufiicient to holdthe tubes-against creeping due to expansion and contraction, to inertiaand to the urge of unidirectional flow through the tubes and does notnormally place the tubes under tension between the tube plates atopposite ends 4 of the condenser. It is not the intention that flaringof the tube ends should so expand the same in the rings 20 as tointerfere with free sliding of the tubes through the rings. It will bereadily understood that, because of the outward flare of the ring bores,the tubes can be expanded, when cold, into substantially fluid tightcontact with the flared surfaces of the rings without interfering withthe free movement of the tubes through the rings as the tubes expandwith heating.

When the tubes are radially expanded, the outer end edges thereof are incontact with the inner ends of the cylindrical bore portions 22 of therings 20. As the tubesexpand longitudinally with heating, the outer andedges thereof maintain contact with the cylindrical bores 22 of therings and exclude mud, scale or'the like from entering between the nowspaced flared portions of the tubes and the flared bore surfaces 2! ofthe rings. Thus, no foreign matter can enter between the flared surfacesand set up tension in the tubes when they 'cool and contract.

When the condenser is assembled, there is a small annular clearance '24around the inner end of each packing sleeve, which clearance tapers tonothing at the outer end of the sleeve, as clearly shown in Figs. 3 and4. In service, moisture penetrates into the intermediate apertureportion l5 and causes the packing to swell radially and fill the spaces24. Thereafter the expansive pressure of the packing is exerted betweenthe tapered wall surfaces and the tubes,

'the effect of the tapered wall surfaces being to serve mainly to holdthe tubes against creeping and against oscillation due to vibration.Vibration of the tubes When in service tends to produce oscillation ofthe tube ends, which oscillation, if unchecked, tends to wear or expandthe packing andcause leaking between the packing and thetubes. The metalrings 20 restrain the tendency to oscillation and thereby protect thepacking. Moreover, the rings seal the outer ends of the packing recessesand retard dryingout of the packing when the condenser is temporarilyout of service, so that there is little or none of the customary leakingwhen the condenser is again put into service.

For the conversion of an existing condenser having the usual internallythreaded packing recesses, designated 25 in Figs. 5 and 6, whether thethreads extend only part way to the inner ends of the recesses, as inFig. 5, or extend to the inner ends, as in Fig. 6, the outer end of thepacking recess may be reamed out to remove the threads to a sufficientdepth to provide a receptacle for the ring 20. If the threads are notremoved in the remainder of the recess to produce the structure of Fig.3, the packing sleeve used, designated 26, is externally threaded tocooperate with the threads of the recess, which then form shouldersretaining the packing in lieu of the tapered wall of Fig. 3. A simplecylindrical packing, as shown in Figs. 3 and 4, is not satis: factory inconnection with an internally threaded recess since, even though thepacking will swell which the threads do not extend to the bottom of therecess. In such case, the packing sleeve Will expand against theunthreaded wall portion with sealing eifect, irrespective of whether theremainder of the sleeve is threaded or not.

Alternatively, to render the invention applicable without alteration tothe tube plate, an externally threaded packing sleeve 26 may be insertedin the packing recess and followed by a tube retaining ring 29*, similarto the ring 29 except that it is externally threaded to cooperate withthe treads of the recess. The tube end is expanded in the ring 29 asalready described for the ring 29.

The assembling of a condenser constructed according to this invention isextremely simple, quick and easy. When the tubes are in place, thepacking sleeves and end rings are easily inserted and cannot beimproperly inserted. The expansion of the tube ends is slight and iseasily accomplished, as by a sharp blow on an expanding tool inserted inthe tube end. The usual expenditure of time and labour in compressingpackings by impact or by inserting and tightening packing nuts isentirely eliminated, together with the uncertainty of the resultthereof.

It will be seen that in all cases the packing swells against the wallsof the packing recesses with retaining effect independently of the endrings and that the tube is held against oscillation at its ends andagainst creeping by the end rings. The thickness of the rings is greaterthan the maximum elongation of the tubes so that even if an expandingtube should carry an end ring with it, the ring will not lose contactwith the wall of its containing recess and will be drawn back into placewhen the tube contracts, thereby to serve as sealing means to retarddrying out of the pack- Claims directed to the packing member 26 and tothe ring members 29 and 29 are presented in a continuation-in-partapplication Serial No. 177,991, filed August 7, 1950. I

Having thus described m invention, I claim;

1. In heat exchangers, including a pair of tube plates apertured forpassage of tubes and tubes passing through said apertures; saidapertures being in their outer portions of larger diameter than thetubes to provide packing recesses around the tubes and packing in saidrecesses; a single rigid metal end ring filling each of the recessesoutside the packing, the bores of said end rings being flared and thetubes being expanded at each end into the flared bore portions of therings, thereby to hold the tubes against creeping.

2. In heat exchangers and the like, tube plates apertured for passage oftubes; tubes passing through said apertures; the said apertures eachhaving an inner portion of tube size and intermediate and outer portionsof greater than tube size, the said intermediate portions havingmutually facing shoulders; packing in said intermediate portionsengageable with said shoulders to be thereby held against displacementin the longitudinal direction of the tubes; said outer aperture portionsbeing of larger diameter than the intermediate portions; and metallicrings filling'said outer aperture portions around the tubes.

3. Structure according to claim 1 in which the packing recesses areinternally threaded and the packing and end rings are externallythreaded to cooperate with said internal threading.

4. In heat exchanger construction including a tube plate apertured forpassage of a tube and a tube passing through said aperture, the aperturebeing in its outer portion of larger diameter than the tube to provide apacking recess around the tube, and packing in said recess; a rigidmetal ring filling the recess outside the packing, said ring having thebore thereof flared in an inner portion of its length and cylindrical inthe outer portion of its length, and the tube end portion being expandedinto the fiared bore portion of the ring and having sliding contact withthe cylindrical portion of the ring bore, thereby to prevent entrance'of solid matter between the flared surfaces of the tube and ring whensuch surfaces are separated due to expansion of the tube.

5. In heat exchanger construction including a tube plate apertured forpassage of a tube and a tube passing through said aperture,the aperturebeing in its larger portion of larger diameter than the tube to providea packing space around the tube and packing in said space; a rigid metalring filling the space outside the packing, said ring having an innercylindrical bore portion in which the tube is a sliding fit, anintermediate portion flaring away from the tube and an outer cylindricalportion larger than the tube, the end portion'of the tube being flaredto conform to the flared portion of the ring bore and having slidingengagement with the outer cylindrical portion of the ring bore, therebyto prevent entrance of solid matter between the flared surfaces of thetube and ring when the same are separated by expansion of the tube.

6. A packing for heat exchangers including tubes and tube plates havinginternally threaded recesses around tube ends providing packingreceiving spaces, said packing comprising an externally threaded,compressed, water swellable fibre sleeve adapted to be screwed into aplate recess in close engagement with a tube and with the bottom andthreaded wall of the recess; and an externally threaded, rigid, metalring adapted to be screwed into the outer part of a plate recess againstsaid packing and to fill the space between the recess wall and the outerend portion of the tube, outwardly of the packing, the bore of said ringbeing at its outer end larger than the tube and tapering inwardly totube size,

. whereby the tube may be expanded into said tapered bore portion tolimit movement of the tube in its axial direction.

HUGH n. HERON.

anraannons crrsn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 510,373 Wheeler Dec. 5, 18931,683,393 Morgan Sept. 4, 1928 1,714,703 Walton May 28, 1929 2,298,154Pennella Oct. 6, 1942 2,420,721 Pennella May 20, 1947 V FOREIGN PATENTSNumber Country Date 539,646 Great Britain Sept. 18, 1941 572,487 GermanyMar. 17, 1933

